IRVING — Emmitt Smith had 11 straight 1,000-yard seasons for the Dallas Cowboys. Since he left, his successors have managed to compile all of one.

The Cowboys also have a grand total of one postseason victory in that span.

So after seeing DeMarco Murray run for more yards than Smith did in a single game — 253, the ninth most in NFL history, and in a game he didn’t even start — it’s easy to understand why everyone around the club is so excited about what the rookie can do next.

It’s not just the highlight plays he might make.

It’s the new dimension he could bring to the offense.

“Teams have to recognize that we can run the ball,” team owner Jerry Jones said.

Smith’s running was the backbone of the Cowboys offense when they won three Super Bowls in four years. As much as it helped having fellow Hall of Famers Troy Aikman and Michael Irvin, everything started with Smith. Many drives finished with him, too.

Of all the rebuilding efforts since those glory years, the biggest missing piece has been a dynamic running back. The leading rushers since then: Troy Hambrick, Julius Jones, Marion Barber and Felix Jones. The only 1,000-yard season was by Julius Jones, in 2006, and it’s not like he blew past the benchmark in totaling 1,084.

Felix Jones was a first-round pick who has shown flashes of great ability. Dallas drafted Murray out of Oklahoma in the third round this April to see whether he could help.

A fast runner and dedicated blocker with great catching ability, Murray slipped to 70th overall because of questions about his durability. Sure enough, he arrived at training camp with a hamstring injury. He missed most of the early practices and the first two preseason games.

His role increased two games ago after Felix Jones was hurt. The more Murray carried the ball, the more of a rhythm he got into, coach Jason Garrett said. So the Cowboys were eager to see what he could do in extended action against the St. Louis Rams.

Tashard Choice got the start, but Murray went in early, with Dallas on its 9-yard line. On his first carry of the game, he went through a hole on the left side and didn’t stop for 91 yards, the second-longest run in franchise history. Over 25 carries, he outran every player in Cowboys history, an illustrious group that includes another Hall of Famer, Tony Dorsett.

Now comes the hard part: doing it again, starting Sunday night in Philadelphia, against defenses that have seen what he can do.

“If he puts a couple of games like that together — whoo! — we’ll have something,” linebacker Bradie James said.

The Cowboys want to see him show he can be a legitimate threat.

“I think it’s unrealistic to say he’s going to be consistently good carrying the ball 253 yards in a game,” Garrett said. “But you think that what he showed yesterday, paired with what we saw of him coming out of school, he’s been a productive back when he’s gotten opportunities.”

The importance of a running game is a staple of Football 101.

“The game slows down when you are able to run the ball,” quarterback Tony Romo said. “Defensively, there’s only so many options they have. ... They have to come down and stop the run. You can’t disguise coverages, you can’t do things nearly as well.”

The best relief would come near the opponent’s goal line. Dallas has struggled to polish off drives with touchdowns since Barber was at his battering-ram best in 2006-07.

A consistent running game helps the rest of the team, too.

There’s an attitude that builds from the offensive line pushing around the defense. It wears out the other guys, mentally and physically, and it drains the clock.

Plus, the defense gets more time to relax on the bench. Just ask Dallas’ defensive players from the mid-’90s how much fresher and better they were thanks to Smith.

This season, the Cowboys might’ve been able to hold onto their 14-point, fourth-quarter lead over the Jets in the opener, or their 24-point, third-quarter lead against Detroit if they could’ve trusted their running game to grind out first downs and keep the clock moving.

Of course, it’s unrealistic to expect all these pieces to snap into place based on one guy after one game.

Remember, Murray is still a novice. He’s played just six NFL games. He’s carried the ball only 49 times, more than half coming in his breakout performance.

And his historic performance came against a bad run defense that was having a particularly bad day.

One thing in his favor is his attitude: pure humility. The day after his breakout performance, he said he hadn’t watched his highlights. But he had studied his lowlights.

“There are definitely a lot of things I need to clean up,” he said.

He also volunteered that he singled out a teammate as a role model: tight end Jason Witten, one of the hardest-working, most-durable players on the team, and a perennial Pro Bowler.

“I copy him, just the way he carries himself on and off the field,” Murray said, adding that his imitation includes using the same supplements. “He’s so focused and he wants to win.”

Witten said the relationship began in training camp when Murray was hurt. Witten gave him tips on how to remain involved so he’d be ready once he got his chance.

“Playing that position, you’ve got to pick up on things quickly,” Witten said. “Obviously we knew he was fast, athletic. But this is a different level. He’s done a great job. He kept his mouth shut and worked and worked and worked.”

Garrett has been tight-lipped about who will start Sunday night against the Eagles in Philadelphia, but he’s vowed to give Murray plenty of carries. (Note to fantasy footballers: five of the eight players ahead of Murray on the single-game rushing list went over 100 yards in their next game.)

Once Jones is back to full strength, the Cowboys could have what they really want: a rotation of running backs, each capable of running away from the defense, each kept fresh — and healthy — by splitting the load.

Garrett also would be able to tinker with things like having them both on the field at the same time, something he dabbled with before Jones got hurt.

“I’m ready to be the No. 1 guy, the No. 2 guy, the No. 3 guy,” Murray said. “Whatever they ask me to do, I’m going to do with a smile on my face.”